October 25, 2014, 10:51:41 AM

Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.


Messages - jrista

Pages: 1 ... 78 79 [80] 81 82 ... 299
1186

Yes, I want a higher MP camera. Yes, I want more DR. Yes, I want better manual focus ability. Yes I want improved AF and yes I want a lot more. But having seen the sharpness, resolution, color and everything else I get from what I have, I wonder if anyone (other than the pixel peepers at CR ;)) will be able to see/tell if I got the new 14 f-stop sensor, with 45MP and ... all the rest of it.


I think your (perfectly reasonable) comment invites two opposite lines of response, both of them right.  If you don't pixel peep (I sometimes wonder if those who disapprove do so because they don't like what they see when they do...), just how much better do images taken with the new Sigma's images look than those taken with other 50mm lenses?  Depending on how you view them, perhaps not much - maybe not at all.  But if you do like pixel peeping (I do, when I like what I see - perhaps there's some AA equivalent: "Hi, my name is X and I like to pixelpeep..."), you will be able to see a difference when you switch sensors (I certainly see a difference when I attach my favorite Canon lenses, such as the 100L, to my Sony A7r, for instance).  Whether the differences are significant, and whether they matter, depends entirely on who's looking.

Can you share your results so we can objectively look at them? (your 100L on the A7r and a Canon dSLR?)

Personally, I feel those who disapprove of pixel peeping indeed do not like what they see when they do- a beautiful image in subject and composition can suddenly be rendered worthless when you start to pay more attention to the minutiae. I think pixel peeping is a good way to waste a good thing.
Let's face it, if your image looks great when fitted to a desktop LCD monitor and you don't plan on an enormous print, what are you gaining by the extra resolution at 100%? What does pixel peeping provide other than vanity? (I regularly pixel peep for my research, but then I am trying to find tiny fluorescent neurons among a ton of luminous gunk)

Pixel peeping has it's place, but it should be thought of as a tool, not the end result. I zoom to 100% when I am denoising or sharpening, to see what the effect looks like at the pixel level. It's how I choose the right attenuation of the various denoising or sharpening settings.

But pixels aren't a picture, they are only components of a picture. You have to look at the whole picture to see the photograph. The problem with "pixel peepers" is that those are the whiny group of individuals who see nothing BUT the pixels, or to steal a phrase "missing the photo for the pixels".

1187
I'd love an interchangeable sensor camera someday ;)

[I know, I know it exists in the MF territory- I'm talking about dSLRs. Although at this time it is counter-productive from a marketing standpoint]

I believe this is what you are looking for.

YIKES!!  :o

1188
EOS Bodies / Re: More Sensor Technology Talk [CR1]
« on: May 01, 2014, 07:50:32 PM »
I don't need tons of megapixels, but if I can't take a picture in complete darkness and recover 24 stops of DR in post this will be a total fail.  Its 2014 Canon! 

 ::)

High ISO is often portrayed - even if only jokingly - like that, but a lot of us wildlife folks (outside of the sunny tropics) could make good use of clean shots in the 12800-25600 range, easily.

At some point I suspect quantum efficiency of sensors will reach the 70-80% level (at least, I hope it happens someday.) Once it does, we can expect a real world improvement of about 2x for high ISO settings. To get any better than that, we would need larger sensors.

I'd settle for another stop - actually roughly what the 1Dx can do (from what I've seen) but with more megapixels for cropping. I once read an article about someone using medium format for bird photography, but I don't think that would be practical for most people, given the extra size lenses would have to be for the same reach (*unless* the extra MP allowed for so much cropping as to cancel it out).

The 1D X does not even get one full stop. It's largely a perceptual thing regarding how good the 1D X looks, but technically, the 1D X is only a fraction of a stop better, and the 5D III when downsampled gets similar results (not quite as good due to less total photodiode area).

When it comes to smaller pixels and croppability, your going to lose high ISO noise performance. I've mentioned this in other topics, but overall, high ISO performance is fundamentally due to total sensor area and quantum efficiency. It is a higher Q.E. and a larger sensor area that makes the 1D X better in the long run, not it's pixel size. Once you bring cropping into the picture, especially with smaller pixels, then you start to experience worsening high ISO performance. Your not only putting fewer pixels on subject, your using a smaller area of the sensor, which means less total light for your subject.

There really isn't any way that a FF sensor with smaller pixels will produce better results than a FF sensor with bigger pixels. It will have more detail, but per-pixel noise will be higher, so cropping means more noise. Cropping a 1D X means less per-pixel noise, but also less detail. It's a tradeoff...low noise, or more detail. For any given sensor area, the only way to improve noise performance is to improve Q.E. The 1D X has 47% Q.E., which means to actually double high ISO noise performance with the 1D neXt, you need 94% Q.E. The 5D III actually has 49% Q.E., which means you need 98% to double it's noise performance. That's not going to happen...not with consumer-grade devices. The highest grade Astro CCD sensors that have 82% Q.E. or more, Grade 1, are exceptionally expensive. They also require significant cooling (usually with two- or three-stage peltier, or themo-electric, cooling), which requires SIGNIFICANT power over what a DSLR normally draws.

Hopes of a super high resolution sensor that performs as well or better than a 1D X when cropped is just a pipe dream. It will resolve more detail, but that detail will be more noisy, not less noisy.

Well that's depressing. How much would you say future improvements in software noise reduction will improve the final output?

Software is a difficult thing to discuss. The biggest reason why is: Which software? There are countless ways of, countless algorithms for, reducing noise. There are your basic averaging/blurring algorithms, your wavelet algorithms, your deconvolution algorithms, etc. Some denoising tools are more complex, and thus more difficult to use effectively, but when used effectively, can produce significantly better results. Some denoising tools are extremely simple, but don't produce as good of results.

Fundamentally, though, pretty much every algorithm suffers from the same core problem, to varying degrees: They blur detail. Your most basic denoising algorithm takes high frequency data and blurs it by a certain amount...for each pixel, it takes some component of the surrounding pixels, generates an averaged result (with some given weight, usually attenuated by some UI control somewhere), and replaces the original pixel value with the weighted average value. Do that for each and every pixel, and each and every pixel ends up blending itself with it's neighboring pixels. There are varying matrix sizes, i.e. 3x3, 6x6, that can be used when performing a very basic noise reduction, that will spread the effect out more or less.

Wavelets and deconvolution tend to be more intelligent about how they reduce noise. They either try to generate a "kernel" based on the information in the image, or try to break up the image into multiple spatial frequency levels, and apply different degrees of noise reduction on each wavelet level, in an attempt to preserve certain frequencies while blurring others, with the ultimate goal of preserving detail. Problem with these algorithms is that, while they can reduce noise without blurring detail as much, they often suffer from greater artifact introduction...halos or excessive acutance or blotching, things like that.

Noise reduction is best applied in extreme moderation, in which case it will always have very significant limitations. It can only take you so far, and the less noisy your images start out as, the better the results will be. This is one of the reasons why the "low" resolution images from the 1D X clean up so well...1D X pixels start out with significantly more dynamic range than sensors with smaller pixels, so there is less per-pixel noise to start with, so a minimal amount of NR is perceived as being more effective (it really isn't, there was less noise to start with, so less noise to remove, so a small amount of NR is has a greater relative effect than with images that start with more noise to remove. In other words, to ridiculously simplify things down to simple numbers, if a 1D X has noise of 7, and a 5D III has noise of 12, and you reduce noise by 5, the 1D X is left with noise of 2, where as the 5D III is left with 7...it's as bad after NR as the 1D X was before NR.)

Noise reduction algorithms are already extremely powerful and extremely intelligent. I recently purchased software called PixInsight, which is primarily an astrophotography processing program, but it's tools can be used  on regular photos as well. It has a whole suite of noise reduction tools that work in different ways. Depending on the kind of noise you have, and the region of your image that you wish to denoise, PixInsights noise reduction tools can be more effective than any other tool...but as advanced as they are, they are still not perfect. Wavelets still introduce mottling and blotching, deconvolution can still introduce halos, median sharpening and denoise can still introduce sparkles and panda eyes, etc.

The best way to reduce noise is to increase the rate of conversion of light to charge in a pixel, increase the maximum charge of each pixel, increase the total maximum charge of the sensor, etc. The more light you can convert into charge in a given time, the less noise you will have. I don't expect to see a major jump in Q.E. any time soon....I suspect Canon's next round of sensors will be around 51-53%, maybe 56% at most, up from the current 47-49%. That will certainly help in the noise department, but it is no where even remotely close to supporting a true one-stop improvement in noise. It's less than a third stop improvement in noise (less than a tenth stop improvement in noise, even!) Elimination of color filters in favor of color splitting, a reduction in heat conversion (i.e. with light pipes or BSI), reduction in reflection (i.e. with black silicon), etc. can all increase the rate at which photons convert to charge, and increase Q.E. These technologies exist, lots of patents exist, however I don't see any patents for these specific kinds of technology from Canon, so I don't expect them to show up in Canon's next sensor designs. A layered sensor is capable of converting more light to charge per pixel, however that charge is divvied up amongst different color channels, so it's effectiveness is attenuated...a foveon-like design from Canon is a step in the right direction, but I don't expect the impact on noise to be all that much (and we'll see a conversion of which color channels are noisiest...instead of blue being noisiest, red is likely to become noisiest, and green will become noisier, while blue would likely experience a modest drop in noise levels.)

1189
EOS Bodies / Re: More Sensor Technology Talk [CR1]
« on: May 01, 2014, 04:26:21 PM »
I think they lost me at "Foveon-like". 

So it will have all the negatives of a high MP camera, like massive files to store, and a slowed FPS, and a faster-clogging buffer, but none of what you actually want from all those MP's, namely higher resolution and more detail to spare when doing things like shooting at high ISO, or cropping heavily.

Am I missing something wonderful about Foveon?  If so, then so is everyone else based on the failure of Sigma's Foveon bodies to fly off the shelves.  Why not copy FUJI sensors instead?  That more complex, non-bayer pixel, no filter thing sounds much more interesting to me, anyway. 

Crud.

Your making a LOT of assumptions. The "negatives" of high MP cameras can be mitigated. With on-die CP-ADC (which canon does have a patent for), they can dramatically improve readout speed (they already proved they could read out a 120mp APS-H sensor at 9.5fps). With CFast 2 technology, we'll have faster write to memory, so the buffer won't necessarily be a problem. With Foveon, we get full color information at every single pixel, full spatial information, no longer need AA filters that are nearly as strong as is usually necessary with Bayer, etc.

Sigma's failure is that they market their product with lies and misleading information, and their bodies/firmware have never been very good (in comparison to Canon and Nikon bodies anyway.) Basing the success of ALL layered sensor designs on Sigma's success is a fallacy.

Fuji's 6x6 pixel interpolation is just another way of blurring high frequency data, only it is LESS effective than a standard AA filter. I covered this in very great detail in a long topic a while back, and the impact of the 6x6 pixel interpolation is quite obvious when comparing fine detail (i.e. hairs, telephone wires, etc.) between Fuji's X-Trans sensor and pretty much any bayer sensor.)

I could care less about what technology "sounds" more interesting. I care about what technology DELIVERS better results. Canon is a very conservative company...if they are going to move to a Foveon-like sensor design, then they must have solved some of the more significant problems that Sigma has encountered, and made it a viable design. They wouldn't bet on it if they hadn't. (And the chances hey HAVE solved many of those problems is very high, Canon has a couple patents on layered foveon-like pixels that use a different structure both for the photodiodes themselves, as well as readout; throw in their patents for on-die per-column dual-rate ramp ADC, and Canon could have a real powerhouse sensor in development that could really give the competition a run for the money...especially if it hits at a literal 40mp (i.e. 120 million photosites in 40 million actual pixels, not a trumped up 40mp like Sigma's Foveon.))

We can hope, a LOT to have overcome, but if they have as well as keeping DR high with that style.... :D could be that Exmor folks are suddenly looking over in envy at Canon sensors for some years to come.

Yeah, it's definitely a LOT to overcome. There is no question at this point that Canon is behind the curve on sensor tech. I watch patents pretty closely these days, and Canon is practically non-existent in the new patent arena. Now, that is not to say that they don't have any. They do...they have Dual-Scale CP-ADC (basically a CP-ADC with two alternate readout rates, as slower readout, when possible (i.e. long enough exposure time to support a slower readout rate) usually results in cleaner read noise (they switch to a lower frequency counter); they have a few patents on layered foveon-style pixels; they have a number of patents on low-noise readout concepts, such as power disconnection (supposedly that can nearly eliminate dark current noise...I'm much more interested in that for astrophotography applications, but it could help a little for very high ISO readout as well).

The big question is, given Canon HAS these patents...will they actually use them in a sensor, and when.

1190
EOS Bodies / Re: More Sensor Technology Talk [CR1]
« on: May 01, 2014, 03:37:40 PM »
I am both a Canon and a Sigma X3F (Foveon) user, and there are good arguments for both sensors. There is no question that the Sigma CAMERAS are deficient in many areas, some not related to the sensor demands, but that for specialized uses, mostly landscapes, the Sigma Foveon cameras have unique qualities making it worthwhile to put up with annoyances. Canon cameras are good all-around cameras, Sigma cameras are specialty cameras.

The Sigma Foveon sensors are perceptually sharper, per pixel, than the Canon Bayer sensors, 15 Mp APS-C DP#M sensor is sharper (slightly) than my FF Canon 6D 20 Mp Bayer sensor, and users of both Sigma and Sony/Nikon FF 24 Mp sensor rank them as similar, with the Sony sensor minimally better in sharpness.

This is a complete fallacy, and easily demonstrable with actual images. I've disproven this concept many times on these forums, recently. I'm happy to use your own images even, but more pixels, even with an AA filter, still leads to greater sharpness. The difference becomes clear when you downsample say the 6D 20mp images to the same image dimensions as the Foveon sensors. Even when your talking about a 15mp (what Sigma calls a 46mp) Foveon, on a normalized basis it isn't as sharp as a bayer.

Foveons strengths are not in the spatial resolution/sharpness category. They are in the color fidelity and moire departments.

The major rendition difference in the Foveon and Bayer sensors in the current iterations is that there is a certain color subtlety in the Foveon sensor RAW files, sometimes called "film-like", that is not present in the Bayer sensor RAW files. Low local contrast, hue-restricted areas are considerably more detailed on the Foveon sensor files than the Bayer sensor files.

This is indeed where the Foveon's strengths truly lie...in color fidelity...richness, saturation, rendition, etc. That's expected, given that each pixel has full color data.

To my mind, the combination of color subtlety and acutance is the one and only reason to go for the Foveon sensor. Foveon sensors excel at landscapes and floral portraits, and are "too sharp" for most portrait use - one is likely to need to do more blemish-removal post-processing than for Bayer sensor files.

Compare a full-resolution D800 (non-E) image with a Foveon image. The D800 will trounce the Foveon (even the 15mp version) in terms of sharpness. The foveon cannot touch "too sharp", the D800 is often so sharp that aliasing becomes a problem (even with the non-E version.)

1191
Sony is making a bigger loss than expected, announced today, and it is rated at junk bond status.

http://www.bbc.co.uk/news/business-27234511
One might imagine -- if Sony's imaging systems are to be sold-off or downsized -- that Canon or Nikon might make a formal play to buy-out their sensor business.

Sony won't be selling off their sensor business. Sensors is what Sony does now, and it's one of their more stable and reliable divisions (even if it isn't making much money.) Sony might sell off other electronics divisions, like they are dumping PCs, they may even sell off their camera business, but I highly doubt Sony will be dumping their sensor business. It's one of the primary reasons their bond status is junk...they have poured billions into sensor fabs and sensor R&D. And like it or not, Sony sensors are beginning to show up everywhere. Video cameras, security cameras, astro imaging cameras, DSLR and mirrorless cameras, etc. Within a decade, the Sony sensor business should be profitable (assuming they slow down on the shotgun approach to R&D and products/markets.)

1192
Sony is making a bigger loss than expected, announced today, and it is rated at junk bond status.

http://www.bbc.co.uk/news/business-27234511

This is no surprise. Sony has been taking a shotgun approach to their markets for a while now. They crank out as many products as they can think of in as many submarkets as they can, and see what sticks. That costs an immense amount of R&D, with no guarantee of payoff.

1193
EOS Bodies / Re: More Sensor Technology Talk [CR1]
« on: May 01, 2014, 12:01:39 PM »
I don't need tons of megapixels, but if I can't take a picture in complete darkness and recover 24 stops of DR in post this will be a total fail.  Its 2014 Canon! 

 ::)

High ISO is often portrayed - even if only jokingly - like that, but a lot of us wildlife folks (outside of the sunny tropics) could make good use of clean shots in the 12800-25600 range, easily.

At some point I suspect quantum efficiency of sensors will reach the 70-80% level (at least, I hope it happens someday.) Once it does, we can expect a real world improvement of about 2x for high ISO settings. To get any better than that, we would need larger sensors.

I'd settle for another stop - actually roughly what the 1Dx can do (from what I've seen) but with more megapixels for cropping. I once read an article about someone using medium format for bird photography, but I don't think that would be practical for most people, given the extra size lenses would have to be for the same reach (*unless* the extra MP allowed for so much cropping as to cancel it out).

The 1D X does not even get one full stop. It's largely a perceptual thing regarding how good the 1D X looks, but technically, the 1D X is only a fraction of a stop better, and the 5D III when downsampled gets similar results (not quite as good due to less total photodiode area).

When it comes to smaller pixels and croppability, your going to lose high ISO noise performance. I've mentioned this in other topics, but overall, high ISO performance is fundamentally due to total sensor area and quantum efficiency. It is a higher Q.E. and a larger sensor area that makes the 1D X better in the long run, not it's pixel size. Once you bring cropping into the picture, especially with smaller pixels, then you start to experience worsening high ISO performance. Your not only putting fewer pixels on subject, your using a smaller area of the sensor, which means less total light for your subject.

There really isn't any way that a FF sensor with smaller pixels will produce better results than a FF sensor with bigger pixels. It will have more detail, but per-pixel noise will be higher, so cropping means more noise. Cropping a 1D X means less per-pixel noise, but also less detail. It's a tradeoff...low noise, or more detail. For any given sensor area, the only way to improve noise performance is to improve Q.E. The 1D X has 47% Q.E., which means to actually double high ISO noise performance with the 1D neXt, you need 94% Q.E. The 5D III actually has 49% Q.E., which means you need 98% to double it's noise performance. That's not going to happen...not with consumer-grade devices. The highest grade Astro CCD sensors that have 82% Q.E. or more, Grade 1, are exceptionally expensive. They also require significant cooling (usually with two- or three-stage peltier, or themo-electric, cooling), which requires SIGNIFICANT power over what a DSLR normally draws.

Hopes of a super high resolution sensor that performs as well or better than a 1D X when cropped is just a pipe dream. It will resolve more detail, but that detail will be more noisy, not less noisy.

1194
EOS Bodies / Re: More Sensor Technology Talk [CR1]
« on: May 01, 2014, 11:23:18 AM »
I don't need tons of megapixels, but if I can't take a picture in complete darkness and recover 24 stops of DR in post this will be a total fail.  Its 2014 Canon! 

 ::)

High ISO is often portrayed - even if only jokingly - like that, but a lot of us wildlife folks (outside of the sunny tropics) could make good use of clean shots in the 12800-25600 range, easily.

At some point I suspect quantum efficiency of sensors will reach the 70-80% level (at least, I hope it happens someday.) Once it does, we can expect a real world improvement of about 2x for high ISO settings. To get any better than that, we would need larger sensors.

1195
EOS Bodies / Re: More Sensor Technology Talk [CR1]
« on: April 30, 2014, 11:11:12 PM »
I think they lost me at "Foveon-like". 

So it will have all the negatives of a high MP camera, like massive files to store, and a slowed FPS, and a faster-clogging buffer, but none of what you actually want from all those MP's, namely higher resolution and more detail to spare when doing things like shooting at high ISO, or cropping heavily.

Am I missing something wonderful about Foveon?  If so, then so is everyone else based on the failure of Sigma's Foveon bodies to fly off the shelves.  Why not copy FUJI sensors instead?  That more complex, non-bayer pixel, no filter thing sounds much more interesting to me, anyway. 

Crud.

Your making a LOT of assumptions. The "negatives" of high MP cameras can be mitigated. With on-die CP-ADC (which canon does have a patent for), they can dramatically improve readout speed (they already proved they could read out a 120mp APS-H sensor at 9.5fps). With CFast 2 technology, we'll have faster write to memory, so the buffer won't necessarily be a problem. With Foveon, we get full color information at every single pixel, full spatial information, no longer need AA filters that are nearly as strong as is usually necessary with Bayer, etc.

Sigma's failure is that they market their product with lies and misleading information, and their bodies/firmware have never been very good (in comparison to Canon and Nikon bodies anyway.) Basing the success of ALL layered sensor designs on Sigma's success is a fallacy.

Fuji's 6x6 pixel interpolation is just another way of blurring high frequency data, only it is LESS effective than a standard AA filter. I covered this in very great detail in a long topic a while back, and the impact of the 6x6 pixel interpolation is quite obvious when comparing fine detail (i.e. hairs, telephone wires, etc.) between Fuji's X-Trans sensor and pretty much any bayer sensor.)

I could care less about what technology "sounds" more interesting. I care about what technology DELIVERS better results. Canon is a very conservative company...if they are going to move to a Foveon-like sensor design, then they must have solved some of the more significant problems that Sigma has encountered, and made it a viable design. They wouldn't bet on it if they hadn't. (And the chances hey HAVE solved many of those problems is very high, Canon has a couple patents on layered foveon-like pixels that use a different structure both for the photodiodes themselves, as well as readout; throw in their patents for on-die per-column dual-rate ramp ADC, and Canon could have a real powerhouse sensor in development that could really give the competition a run for the money...especially if it hits at a literal 40mp (i.e. 120 million photosites in 40 million actual pixels, not a trumped up 40mp like Sigma's Foveon.))

1196
EOS Bodies / Re: New Sensor Technology Coming From Canon? [CR1]
« on: April 30, 2014, 01:17:50 PM »
Why do the etchings always have to go in the same direction?
I guess it's how are they cut out? what do they use, a saw  ;D

Well, there is no specific reason why they couldn't etch some additional sensors in the perpendicular direction, but it would be costly. The way sensor fabrication works is by etching the silicon with extreme UV light via a template. The template is oriented in a single direction. The wafer is moved underneath the light beam so that multiple sensors can be etched. Etching of a single sensor is a multi-step process, with various steps involving masking, etching, dissolution of masks, more etching, doping and layering of new materials, masking, etching, etc. This stuff has to be precise to the level of a few nanometers at most, so it is entirely automated. Rotating the wafer to etch additional sensors in a different direction introduces a source of error that could hurt yield.


1197
EOS Bodies / Re: New Sensor Technology Coming From Canon? [CR1]
« on: April 29, 2014, 11:28:57 PM »

Surface area of FF => 864mm^2
32429/864=47.41

If they can only get 20 FF sensors out of that, they have about 58% losses. 

This is an 8 year old white paper and nobody mentioned these mistakes before?

That's very interesting if indeed that does translate to about 58% full frame sensor losses per wafer, even if it was 8 years ago.

I made a mistake (maybe Canon has a job offer ;-)), corrected it in my last post. It should be

Surface area of FF => 864mm^2
32429/864=37.5

If they can only get 20 FF sensors out of that, they have about 47% losses.

It isn't exactly 47% loss. It's 64% of the area is actually used to print FF sensors. If this diagram is any indication, then they actually ETCH exactly 24FF, or 80APSC on a single 200mm wafer:



The actual losses would be out these numbers...so accounting for defects and whatnot, actual FF yield would have to be less than 24, and actual APS-C yield would have to be less than 80. Assuming they actually get 20 FF out of 24, the loss is 16.7%.

That assumes that the article was clear about the size of wafer used to produce APS-C sensors...which it is not. Since a 300mm wafer can handle about 212 APS-C sensors, and since the article states that around 200 APS-C sensors are made from each wafer, it makes sense that Canon is manufacturing APS-C sensors on 300mm wafers, rather than 200mm wafers. Either way, they clearly have a higher yield off smaller sensors.

1198
EOS Bodies / Re: New Sensor Technology Coming From Canon? [CR1]
« on: April 29, 2014, 05:55:07 PM »
It depends on what the improvement is and how much it costs to implement.  The rumor (although likely false) suggests an improvement in yield, which is where there's a major difference between FF and APS-C.  Sensors are cut from round silicon wafers, and according to Canon a single wafer can produce 20 FF sensors or ~200 APS-C sensors. 

HMM! This is interesting. If Canon is producing ~200 APS-C sensors per wafer, and only 20 FF sensors per wafer, then that means they are already producing APS-C sensors on 300mm wafers, but are still producing FF sensors on 200mm wafers. If you run the numbers, the raw number of full APS-C sensors on a 200mm wafer is 94, on 300mm wafer is 212; the raw number for full Ff sensors on 200mm wafer is 36, on 300mm wafer is 81. Factor in losses, you get a bit less than 200 APS-C/300mm wafer, maybe 20 FF/200mm wafer. I suspect that the actual number of total FF sensors is less than 36, since every time I've seen a photo of large sensors on a wafer, there is usually plenty of blank space and an unetched border around the edge. So maybe Canon gets 190 APS-C out of a 300mm wafer, and indeed only about 20 FF out of a 200mm wafer. Assuming similar losses with larger wafers, Canon should get almost 70 FF sensors out of a 300mm wafer if they do indeed make the move.

How about a hypothetical example…  Say it costs $20,000 for the raw silicon wafer and the stamping and cutting (I have no idea how wild-assed that guess is).  That means a FF sensor costs $1000 and an APS-C sensor costs $100.  Now, say there are on average two random local defects per wafer that result in the loss of the sensors where they occur.  FF production takes a 10% hit on yield, whereas APS-C takes only a 1% hit on yield.  Taking QC defects into account, the cost of a FF sensor is $1111 and an APS-C sensor is $101.  Now, suppose this new process cuts the defect rate in half, to one per wafer, and increases production costs by 2% per wafer.  That drops the cost of a FF sensor to $1074, a 3.3% savings.  However, that 'improvement' results in an APS-C cost per sensor of $102.50, an increase of 1.5% per sensor for APS-C production.

Sell 5,000,000 FF cameras and save $37 each and that's a 185 million dollar profit….
Sell 100,000,000 APSC cameras and spend an extra $1.50 each and that's a 150 million dollar loss....

Now which pile of money do you think Canon would go for first?   :)

Granted, this is only a hypothetical example.  Hwever, it does demonstrate one scenario in which application of a process improvement for FF production would not be cost-effective when applied to APS-C production.

I totally agree. I think increasing yield on the FF sensor front is really where they can save the most money, especially if they are still using 200mm wafers. They have to waste a proportionally much larger area of a 200mm wafer than a 300mm wafer when fabbing FF sensors.

1199
EOS Bodies / Re: New Sensor Technology Coming From Canon? [CR1]
« on: April 29, 2014, 01:58:29 PM »
Even simpler to explain how full frame could work, with unclipped corners, using the M mount: the imaging light is projected from the lens to the sensor from the last element at the back of the lens, which is, I think, always situated slightly behind the plane of the lens mount, not at or in front of the plane of the lens mount. Simple. All other explanations are surely true, but none, other than the above, is necessary.

There are problems with designing lenses this way, though. The closer to the sensor plane the backmost elements are (or, for that matter, the exit pupil is), the more angled the light has to be to reach the periphery of the sensor. The larger the sensor, greater that angle is. Highly angled light doesn't flow into the pixel wells (for FSI designs), and it is difficult to create microlenses with a great enough power to bend the light back into the well. For BSI designs, the high angle of light results in a significantly greater amount of reflection rather than refraction, so the light is simply lost. This increases vignetting in the corners. The Sony FF mirrorless options have this problem. Sony has tried to mitigate the issue by using differently designed microlenses in the periphery, however it is only a mitigation, not a solution to the problem.

Another problem with lens elements being mounted so close to the sensor plane is ghosting. A lot of ghosted light that reflects off the sensor is so dim that the inverse square falloff law results in it being invisible, for all intents and purposes, once it reflects off the back lens elements and back onto the sensor. With a much shorter sensor to back element distance, ghosting becomes a much greater problem. This actually occurs with most mirrorless designs today, including the EOS-M and Sony A7 series.

As much as everyone seems to want smaller and smaller and more compact cameras, making cameras that way has it's tradeoffs, it's cons. There isn't anything simple about creating pancake lenses that could work ideally for full-frame sensors in a mirrorless design. The benefits of using larger camera bodies with larger flange-to-sensor distances is you don't have these problems. A large flange distance, such as 44mm for Canon DSLRs, means light, even for a FF sensor, never has to reach significant angles, making microlensing on the sensor far more effective at guiding light down to the photodiodes. The greater distance results in a longer distance for reflected light to fall off and not cause ghosting.

I think it will be interesting to see how a FF Canon Mirrorless fares with purpose-built lenses. I suspect we'll see many of the same problems that the Sony FF mirrorless cameras experience. Canon has superior lens design capability vs. Sony, so in the long run I think they could build better lenses for a FF mirrorless system...but there are physical limitations for lenses just as much as there are physical limitations for sensors.

1200
EOS Bodies / Re: New Sensor Technology Coming From Canon? [CR1]
« on: April 29, 2014, 12:42:26 PM »
I agree. I've never understood people's fascination with using a FF sensor in an M-mount camera. It always seemed more reasonable to just shorten the flange-sensor distance and use the EF mount. Just getting rid of the mirror box will allow significant size and weight reductions. I don't see how the M-mount would make that much of a difference.

EF (and EF-S) lenses are designed with a 44mm flange focal distance.  If Canon makes a FF mirrorless with that same flange focal distance, they'll use the same mount.  If they make one with a shorter flange focal distance (it's 18mm for EF-M lenses, for example), they'll make a new mount for the same reason they designed the system so EF-S lenses don't mount on FF bodies - to avoid confusion and unexpected results.  They might try squeezing the FF mount into the EF-M size, so that the new FF-mirrorless lenses could be used directly on EOS M or other APS-C mirrorless, in the same way that EF lenses can be used on APS-C dSLRs.  In particular, it the whole ecosystem does shift to mirrorless, longer lenses don't really benefit from a smaller image circle, so having a mount compatible with larger and smaller sensors makes sense.

Totally agree.

Pages: 1 ... 78 79 [80] 81 82 ... 299